Merge lp://qastaging/~dshea/timezonemap/location-cycle into lp://qastaging/timezonemap

An anaconda user noticed (https://bugzilla.redhat.com/show_bug.cgi?id=1190265) that if you repeatedly click the same spot on the map, it will choose different locations for each click (which is intentional), to the point where clicks will start jumping wildly across the map as the search area expands outwards (which is probably less intentional). While looking into this, I found that the handling of the repeated clicks resulted in a memory leak in priv->distances, and if you managed to get to the end of the list it would crash. The first patch addresses the memory problems, and the second limits the location search to a 50px radius.